It is likely that most conversions will be CPU bound rather than RAM limited.

One thing that may be a limiting factor is disc speed combined with disc cache. This is why 32 bit calibre on 64 bit windows isn't all that bad. Unused memory will go to disc cache. You may be able to compensate quite a bit for slow discs by having plenty of memory for disc cache. This might even mean that 64 bit calibre could sometimes be slower than 32 bit calibre on computers with slow discs and limited memory (less than 8GB?)?

When doing very large bulk conversions the disc cache may currently be poorly utilized?

I don't know exactly how Calibre handles large bulk jobs, but it seems that when you transfer to device or convert, all the books are read and copied to the temp folder, and modified there. Only when all books have been converted or updated, and are ready in temp, does the transfer to device or back to the library start. If there are many books the cache may have discarded the first books in temp before this happens. Perhaps Calibre would be perceived as being much faster if the books were processed fully one by one. Copied to temp, modified, copied to destination, deleted in temp, and repeat for next book. Then it would be more likely that the cache can be utilized fully, and if temp and the library are on different discs, more of the file transfer may be done in parallel. But perhaps this would increase the risk of corrupt books or metadata?

Just a quick note for those thinking about installing the 64 bit. I just installed it, an the installer looked at everything I had already set up. I did not have to use any wizard to point to my existing library or re-load my plug-ins. Kovid designed it so that if you had a preexisting installation, all the libraries and plug-ins from your 32 bit would be immediately available in the 64 bit. Since Kovid originally said that the two versions could be run and installed at the same time, I had made the assumption that the 64 bit would require configuration upon installation even if you had the 32 bit version installed. It didn't require any special configuration and it's working great on my system so far.
I must say a huge thank you for making the installation seamless and stress free.

Just a quick note for those thinking about installing the 64 bit. I just installed it, an the installer looked at everything I had already set up. I did not have to use any wizard to point to my existing library or re-load my plug-ins. Kovid designed it so that if you had a preexisting installation, all the libraries and plug-ins from your 32 bit would be immediately available in the 64 bit. Since Kovid originally said that the two versions could be run and installed at the same time, I had made the assumption that the 64 bit would require configuration upon installation even if you had the 32 bit version installed. It didn't require any special configuration and it's working great on my system so far.
I must say a huge thank you for making the installation seamless and stress free.

I don't think ' he said 'Run at the same time'.
You can have Both version Installed .

He did say that they shared the configuration folder (no smart installer needed. existing configurations are not overwritten.)

I don't think ' he said 'Run at the same time'.
You can have Both version Installed .

He did say that they shared the configuration folder (no smart installer needed. existing configurations are not overwritten.)

You are right. I did mean to say both versions Installed at the same time. I have tried (by accident of course ) to run both versions at the same time. With 64 running, clicking on the 32 bit icon will do absolutly nothing

I have come to expect that different version of code, require different configurations, re-setting up, et cetera, over the years. It is a very refreshing breath of fresh air to have someone develop with ease of use in mind.

The only thing I discovered is that when prompted to update to the latest 0.9.9 version it took me to the 32bit download.

Of course I didn't notice this until all of a sudden I was back to 2 versions of calibre. And no the irony of someone not bothering to read when it involves a program designed for people who read is not lost on me :-)

The only thing I discovered is that when prompted to update to the latest 0.9.9 version it took me to the 32bit download.

Of course I didn't notice this until all of a sudden I was back to 2 versions of calibre. And no the irony of someone not bothering to read when it involves a program designed for people who read is not lost on me :-)

Robin
The 'Get Update' will try and update the current running version.
When I start from 'portable', that is the update I see.
When I start from 32bit, yup! 32bit.

There may be reasons you are NOT wanting to run a different system version.

Robin
The 'Get Update' will try and update the current running version.
When I start from 'portable', that is the update I see.
When I start from 32bit, yup! 32bit.

There may be reasons you are NOT wanting to run a different system version.

Hmmm. I'll wait until the next update but I am 100% positive I was running the 64 bit when I clicked on the update as I had already uninstalled the 32bit version having seen no reliability issues in the period I had been using the 64bit version. In fact, after "updating" the first time, when I reopened 64bit it took me right back to the regular 32bit windows page for download. I simply clicked on the "other versions" to get to the 64bit download.

Hmmm. I'll wait until the next update but I am 100% positive I was running the 64 bit when I clicked on the update as I had already uninstalled the 32bit version having seen no reliability issues in the period I had been using the 64bit version. In fact, after "updating" the first time, when I reopened 64bit it took me right back to the regular 32bit windows page for download. I simply clicked on the "other versions" to get to the 64bit download.

Glad to see it works for others, but 64 bit does not work at-all for me.
I un-installed 8.63. (BTW 8.63 worked fine). I rebooted, & installed 9.9 to a new directory.
I double clicked on the launcher, and it opened the splash screen, and hung there.

I rebooted again, now it will not even show the splash screen. I will try some more with the debug option. But first a sanity check: MUST I install the 32-bit version as well?

Odd odd odd!
I started with calibre-debug -g, it reported it was frozen. I killed everything with task manager. I tried again, it started right up no problem. I stopped & restarted it in debug mode. Again, no problem. I restarted from the desktop GUI, and now the normal mode works fine too.
So, for now, its fine. I guess that's good.

If you went from (32 bit) 8.63 to 9.9 there is a good possibility there were (intense) post-upgrade install tasks running.
There were file name corrections (happened due to a bug), sometimes upgrades perform DB structure changes.
I don't ever remember Calibre popping a 'Please wait (and don't kill this), while the DB upgrade completes' message. You went from 1 release level (8) to another (9), give it at least as long as a full 'Library check' takes before worrying

One thing that may be a limiting factor is disc speed combined with disc cache. This is why 32 bit calibre on 64 bit windows isn't all that bad. Unused memory will go to disc cache. You may be able to compensate quite a bit for slow discs by having plenty of memory for disc cache. This might even mean that 64 bit calibre could sometimes be slower than 32 bit calibre on computers with slow discs and limited memory (less than 8GB?)?

I have a quad core AMD 2.90 MHZ, 16 G Kingston HyperX Ram. My HD is a 7200 RPM Hitachi with 32 MB Buffer, SATA II , 3.0 Bb/s. Just processed 10 AZW>MOBI ebooks, and all 4 processors max-ed out at 100%, RAM usage peaked at 3.4% of 16 G, 14G available. I know the 'puter isn't a sure 'nuff screamer, but it's not a hunk of junk, either.
When doing very large bulk conversions the disc cache may currently be poorly utilized?

I don't know exactly how Calibre handles large bulk jobs, but it seems that when you transfer to device or convert, all the books are read and copied to the temp folder, and modified there. Only when all books have been converted or updated, and are ready in temp, does the transfer to device or back to the library start. If there are many books the cache may have discarded the first books in temp before this happens. Perhaps Calibre would be perceived as being much faster if the books were processed fully one by one. Copied to temp, modified, copied to destination, deleted in temp, and repeat for next book. Then it would be more likely that the cache can be utilized fully, and if temp and the library are on different discs, more of the file transfer may be done in parallel. But perhaps this would increase the risk of corrupt books or metadata?

All of the conversions were accomplished properly, and as the processes were eliminated to 3 cores processing, the fan speed slowed some, but 3 cores continued at 100%. RAM usage didn't change. It's the RAM usage that I need to improve, but I don't know how.

This must not be a problem with anyone else, for no one seems to have voiced a problem. However, I'd like, if possible, to improve this process. I just ordered an aftermarket cooler for the system that should keep the processors cool during the conversions, but, still.....DAD GUMMIT, I'd like to take advantage of all that extra RAM not doing anything!

I just installed 64bit version and tried to open a mobi file with the viewer.
Immediately, a "calibre-parallel.exe stop working" dialog show up reporting a BEX64 problem.
And then the calibre.exe crashed itself.
But the previously intalled 0.9.8 32bit version still works well